A study looking at older adults with chronic pain found no significant difference in cognitive performance when comparing them with matched patients who did not use medical cannabis.
A recent study examined the effect of long‐term medical cannabis (MC) use in middle-aged and older patients with chronic pain to see if there is an effect on brain health, particularly cognitive function.
The use of MC is growing in this age group, the authors noted. In the United States, people aged 60 and over account for about 20% of patients using MC; in Israel, about a quarter of patients using MC are over age 65.
Chronic pain is driving the use of MC. In the United States, it is the most common reason patients seek out MC.
Current knowledge about the effects of cannabis on the brain come from studies of adolescents and young adults; these studies show that cannabis is linked with long‐term cognitive impairment, particularly in those who start using it at younger ages. Although the effect on cognition on older adults is unknown, the authors pointed out that older brains are fundamentally different, as they have already gone through many changes in terms of global and regional volumes and neural activity patterns.
In addition, they cited other early studies indicating that some benefit to the brain and neurocognition may be gained from cannabis as well as cannabidiol (CBD) and delta‐9‐tetrahydrocannabinol (THC).
The current study was carried out in Israel on patients aged 50 and above, with and without permission to use MC, through the country’s licensing procedure. Chronic pain is particularly prevalent among older adults and makes up the largest group of patients in Israel using MC, so researchers recruited patients from the Rambam Institute for Pain Medicine in Haifa, Israel. The sample included 63 patients with a license for MC and 62 without.
The average age of the group was 61.37 (5.93) years and 61 (48.8%) were men.
Patients using MC were slightly older than those without a license (63  vs 60  years; P = .003). They were also more likely to have cardiovascular disease (11% vs 3%; P = .025) and depression (21% vs. 7%; P = .003). There was no significant difference in other characteristics between the 2 groups, including education level or use of alcohol and tobacco.
Cognition was assessed through the use of CogState, a brief computerized series of tests to assess performance of psychomotor reaction, attention, working memory, and new learning.
Patients were asked to abstain from cannabis use 3 hours before the test, but the average amount of time patients abstained for was 11 hours.
Results showed there was no significant difference in cognitive performance between the 2 groups; in addition, in an analysis of only the licensed cannabis users, there was no difference when looking at years of MC use, frequency of use, hours since last use, number of strains used, THC/CBD concentration, or dose.
The study had certain limitations. It was observational with a cross‐sectional design, and no cause‐effect inferences could be made; the cognitive assessment was brief; and no information about other pain-relieving drugs or psychoactive medicines was collected.
Given an aging population, longer life expectancy, shifting public attitudes about MC, and growing evidence about the benefits of MC for certain chronic health conditions, the authors argued that their findings “could be a first step towards a better risk–benefit assessment of MC treatment in this population.
Sznitman SR, Vulfsons S, Meiri D, Weinstein G. Medical cannabis and cognitive performance in middle to old adults treated for chronic pain. Drug Alcohol Rev. Published online September 22, 2020. doi:10.1111/dar.13171